Laminated film and packaging container

ABSTRACT

A laminated film including: an inner layer which is formed of a linear low density polyethylene resin and is heat-sealable; an outer layer which is laminated on the inner layer; a fragile processed portion which is formed by laser irradiation to the outer layer and has a depth reaching at least an inside of the outer layer and not penetrating the inner layer; and an intermediate layer which is provided between the inner layer and the outer layer, wherein the intermediate layer is an ink layer for reducing a lamination strength between the inner layer and the outer layer, and is formed in a region excluding the fragile processed portion and excluding a periphery of the fragile processed portion in planar view.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Divisional Application of U.S. application Ser. No. 14/679,238filed Apr. 6, 2015, which is a continuation application based on PCTPatent Application No. PCT/JP2013/077945, filed Oct. 15, 2013, whoseforeign priority is claimed on Japanese Patent Application No.2012-228075, filed Oct. 15, 2012, the entire contents of which arehereby incorporated by reference.

BACKGROUND OF INVENTION Field of Invention

The present invention relates to a laminated film, and moreparticularly, to a laminated film that is used in a packaging containerso that the contents can be appropriately heated in a microwave oven anda packaging bag using a laminated film.

Description of Related Art

There are various foods that are contained in a packaging container,such as a packaging bag, in a cooked or semi-cooked state so as to beable to be stored at room temperature, or at a low temperature, or in afrozen state and that can be eaten by being heated in a microwave ovenwithout being opened.

When the packaging container is heated in the microwave without beingopened, moisture in the packaging container becomes water vapor.Accordingly, the volume of the packaging container is increased. Forthis reason, there is a risk of rupture or the like of the packagingcontainer if there is no gap through which water vapor can bedischarged. On the other hand, when the contents are in a semi-cookedstate or the like, it may be necessary to not only simply heat thecontents but also steam the contents with the generated water vapor. Inthis case, if a hole or the like for discharging vapor is excessivelylarge, steaming is not sufficiently performed. Accordingly, there is aproblem, such as a reduction in the taste.

Some packaging bags corresponding to the above applications are known.All of these packaging bags are generally formed using a laminated film.When internal pressure increases, a crack is generated in a part of thelaminated film, and water vapor is discharged through the crack. Thus,rupture is prevented.

As a packaging bag in which the contents can be steamed during theheating by a microwave, for example, a packaging bag disclosed in PCTInternational Publication No. WO2012/086295 is known. In the packagingbag, a slit passing through an outer layer and an inner layer is formedin a part of a laminated film having the outer layer and the inner layerand then the inner layer is heated and melted so that only the slit ofthe inner layer is closed. When heating the packaging bag in themicrowave, the inner layer tears and a small hole is formed. Therefore,since water vapor is not excessively discharged, it is possible toperform steaming while preventing rupture.

However, although it is possible to perform steaming while preventingrupture in the packaging bag disclosed in PCT International PublicationNo. WO2012/086295, processing on the formation and re-fusing of the slitis complicated. Therefore, the manufacturing process is complicated, andit is difficult to improve the manufacturing efficiency. In addition, itis difficult to guarantee the sealing quality after re-fusing.

SUMMARY OF INVENTION

The invention has been made in view of the above situation, and it is anobject of the invention to provide a laminated film that can be appliedto a packaging container in order to prevent rupture during the heatingby a microwave and that can be easily manufactured.

It is another object of the invention to provide a packaging containerthat can prevent rupture during the heating by a microwave and that canbe easily manufactured.

According to a first aspect of the invention, there is provided alaminated film including: an inner layer which is formed of aheat-sealable thermoplastic resin; an outer layer which is laminated onthe inner layer; and a fragile processed portion in which at least apart of the outer layer is removed and at least a part of the innerlayer is present and which has a linear shape in planar view and aYoung's modulus of 2.0 gigapascals or less.

According to a second aspect of the invention, there is provided alaminated film including: an inner layer which is formed of a linear lowdensity polyethylene resin and is heat-sealable; an outer layer which islaminated on the inner layer; and a fragile processed portion in whichat least a part of the outer layer is removed and at least a part of theinner layer is present and which has a linear shape in planar view and aYoung's modulus less than 2.8 gigapascals.

A lamination strength under a heating environment near the fragileprocessed portion may be equal to or greater than 0.1 N/25 mm.

The fragile processed portion may be formed by laser irradiation.

In addition, the laminated film according to the first or second aspectof the invention may further include an intermediate layer which isprovided between the inner layer and the outer layer.

In this case, the intermediate layer may be an ink layer for reducing alamination strength between the inner layer and the outer layer and maybe formed in a region excluding the fragile processed portion and aperiphery of the fragile processed portion in planar view, or theintermediate layer may be a strong lamination layer increasing alamination strength between the inner layer and the outer layer and maybe formed in a region including both sides of the fragile processedportion in a longitudinal direction of the fragile processed portion inplanar view.

According to a third aspect of the invention, there is provided apackaging container including the laminated film according to the firstaspect of the invention, and a plurality of small holes are configuredto be formed in the fragile processed portion during heating by amicrowave.

By applying the laminated film according to the aspects of the inventionto the packaging container, it is possible to prevent rupture during theheating by the microwave. In addition, the laminated film according tothe aspect of the invention can be easily manufactured.

In addition, according to the packaging container according to theaspect of the invention, it is possible to prevent rupture during theheating by the microwave. In addition, the packaging container accordingto the aspect of the invention can be easily manufactured.

In addition, according to the laminated film or the packaging containeraccording to the aspect of the invention, it is possible to performsteaming satisfactorily during the heating by the microwave by applyingthe laminated film to the packaging container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a packaging bag formed by using alaminated film according to a first embodiment of the invention.

FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1.

FIG. 3 is a schematic diagram showing a test piece when measuring theYoung's modulus of a fragile processed portion.

FIG. 4 is a diagram showing a fragile processed portion when heated in amicrowave.

FIG. 5A is a cross-sectional view in a modification example of thelaminated film.

FIG. 5B is a cross-sectional view in a modification example of thelaminated film.

FIG. 6A is a partial plan view of a laminated film according to a secondembodiment of the invention.

FIG. 6B is a cross-sectional view taken along the line B-B of FIG. 6A.

FIG. 7A is a plan view showing an inner layer in a modification exampleof the laminated film.

FIG. 7B is a plan view showing an inner layer in a modification exampleof the laminated film.

FIG. 7C is a plan view showing an inner layer in a modification exampleof the laminated film.

FIG. 8A is a plan view showing a fragile processed portion of thelaminated film according to the embodiment of the invention.

FIG. 8B is a plan view showing a fragile processed portion of thelaminated film according to the embodiment of the invention.

FIG. 8C is a plan view showing a fragile processed portion of thelaminated film according to the embodiment of the invention.

FIG. 8D is a plan view showing a fragile processed portion of thelaminated film according to the embodiment of the invention.

FIG. 8E is a plan view showing a fragile processed portion of thelaminated film according to the embodiment of the invention.

FIG. 9 is a perspective view showing a modification example of apackaging container of the invention.

DESCRIPTION OF EMBODIMENTS

A laminated film and a packaging container according to a firstembodiment of the invention will be described with reference to FIGS. 1to 5B.

FIG. 1 is a perspective view showing a packaging bag (packagingcontainer) 1 of the present embodiment. The packaging bag 1 is formed ina bag shape using a laminated film 10 having at least one surface thatcan be heat-sealed.

The packaging bag 1 of the present embodiment is formed in a bag shapeby heat-sealing ends 10 a and 10 b of one rectangular or squarelaminated film 10 in an approximately cylindrical shape and then bondingboth ends 10 c and 10 d in a direction in which the space of thecylindrical shape extends by heat-sealing.

In the packaging bag of the present embodiment, procedures and methodsfor forming the laminated film in a bag shape are not particularlylimited. For example, a packaging bag may be formed by arranging twolaminated films so as to face each other and bonding the peripheralportions by heat-sealing, or other methods may be used.

FIG. 2 is a cross-sectional view of the laminated film 10 taken alongthe line A-A of FIG. 1. The laminated film 10 is formed by laminating anouter layer 20, which forms the outer surface of the packaging bag 1,and an inner layer 30, which forms the inner surface of the packagingbag 1 and which is heat-sealable. Both the outer layer 20 and the innerlayer 30 are formed of a resin.

As a resin for forming the outer layer 20, a material having arelatively high rigidity is preferable in terms of protecting thecontents. For example, polyethylene terephthalate (PET), biaxiallyoriented polypropylene (OPP), and biaxially oriented nylon (ONy) can beused. However, resin materials for forming the outer layer 20 are notlimited thereto.

Secondary processing, such as printing or vapor deposition, may beperformed on the outer layer 20 in order to improve the design ordisplay various kinds of information. Such secondary processing may beperformed on any of the front and back surfaces of the outer layer 20.

The inner layer 30 functions as a so-called sealant layer. Therefore, asa resin for forming the inner layer 30, it is possible to use aheat-sealable thermoplastic resin, for example, various knowngeneral-purpose polyolefines and special polyolefines. As specificexamples, linear low density polyethylene (LLDPE), low densitypolyethylene (LDPE), medium density polyethylene (MDPE), high densitypolyethylene (HDPE), very low density polyethylene (VLDPE), unstretchedpolypropylene (CPP), ethylene vinyl acetate copolymer (EVA), ethyleneacrylic acid copolymer (EAA), ethylene methacrylic acid copolymer(EMAA), ethylene ethyl acrylate copolymer (EEA), ethylene methylmethacrylate copolymer (EMMA), ethylene methyl acrylate copolymer (EMA),and ionomer (TO) can be used. However, resin materials for forming theinner layer 30 are not limited thereto.

When linear low density polyethylene (LLDPE) that is a heat-sealablethermoplastic resin is used as a resin for forming the inner layer 30,the impact fracture mass of the inner layer 30 is 100 g or more and 800g or less, more preferably, 100 g or more and 700 g or less.

In the embodiment of the invention, the impact fracture mass is definedas a value measured according to JISK7124 “impact test method accordingto the dart method of free fall of plastic film and sheet”.

The outer layer 20 and the inner layer 30 are bonded to each other byarranging an adhesive layer (not shown) therebetween and performingknown dry lamination processing. The method of laminating the outerlayer and the inner layer are not particularly limited. For example, aswill be described later, the outer layer and the inner layer may belaminated using a sandwich lamination method in which another resin isinterposed between the outer layer and the inner layer or a coextrusionmethod.

As shown in FIGS. 1 and 2, a fragile processed portion 40, which isformed by removing at least a part of the outer layer 20, is provided ina part of the outer surface of the packaging bag 1. In the fragileprocessed portion 40, the outer layer 20 is removed in a region having,for example, a width wl of approximately 150 micrometers (μm) and alength 11 of 40 millimeters (mm), and a groove 40 a is formed in theregion. The fragile processed portion 40 in the present embodiment is aportion that is located in the groove 40 a of the laminated film 10 andis thinner than other portions. In the fragile processed portion 40, theentire outer layer 20 is generally removed.

In the fragile processed portion 40, a Young's modulus (tensile elasticmodulus) shown as a slope of the stress-distortion straight line perunit cross-sectional area is low compared with other portions of thelaminated film 10 since the outer layer 20 has been removed.Accordingly, the fragile processed portion 40 tears easily.Specifically, the Young's modulus of the fragile processed portion 40 isequal to or less than 2.0 gigapascals (GPa) in the measurementconforming to JISK7127. In particular, when using the linear low densitypolyethylene (LLDPE) as a resin for forming the inner layer 30, theYoung's modulus of the fragile processed portion 40 is less than 2.8gigapascals (GPa) in the measurement conforming to JISK7127.

The lower limit of the Young's modulus of the fragile processed portion40 is not particularly limited. When the Young's modulus of the fragileprocessed portion 40 is lower than the Young's modulus of the innermonolayer, the fragile processed portion may be broken by impact, suchas dropping, which is not desirable.

In JISK7127, the size of the test piece is determined. Accordingly, itis difficult to measure the Young's modulus of only the fragileprocessed portion according to JISK7127. Therefore, in the invention, aYoung's modulus measured according to JISK7127 using a test piece Spshown in FIG. 3 is defined as the Young's modulus of the fragileprocessed portion. In the test piece Sp, the fragile processed portion40 is formed in the middle of the laminated film 10, which is cut to thesize set in JISK7127, in the longitudinal direction so as to extend inthe width direction of the laminated film 10. In addition, thecross-sectional area used to calculate the Young's modulus of thefragile processed portion is calculated using the thickness of thefragile processed portion.

In the embodiment of the invention, the outer layer removal amount orprocessing depth in the fragile processed portion is not particularlylimited as long as the Young's modulus satisfies the conditionsdescribed above. For example, a thin outer layer may remain over theentire surface of the fragile processed portion so that the inner layeris not exposed, or not only the outer layer but also a part of the innerlayer may be removed. In this case, in order to prevent the leakage ofthe contents before heating the contents in the microwave, the fragileprocessed portion is formed so as not to pass through the inner layer.That is, at least a part of the outer layer may be removed and at leasta part of the inner layer may remain so that the Young's modulus of thefragile processed portion satisfies the conditions described above.

For a position where the fragile processed portion 40 is formed, anyportion such as the ends 10 a to 10 d, which is different from a portionheat-sealed to form the laminated film 10 in a bag shape, may beselected. The fragile processed portion 40 can be formed at any positionin consideration of the type of the contents, a filling process, and thelike.

In the diagrams, a case is shown in which the fragile processed portionis formed in one straight line shape. However, the shape of the fragileprocessed portion is not limited thereto. For example, the shape of thefragile processed portion may be a curved line shape or a zigzag lineshape or two or more fragile processed portions may be formed as long asthe conditions of the Young's modulus described above are satisfied. Inaddition, in the diagrams, a case is shown in which the fragileprocessed portion is a continuous line. However, the fragile processedportion may be formed in a broken line shape or the like as long as theconditions of the Young's modulus described above are satisfied.

As a method of forming the fragile processed portion 40, laserprocessing based on laser irradiation is preferable. If the laserprocessing is used, the shape and processing depth of the fragileprocessed portion can be adjusted relatively easily by adjusting theoutput and scanning speed of the laser head. Here, forming means is notlimited to the laser processing, and it is also possible to use othermethods.

The laminated film 10 having the fragile processed portion 40 formed atan arbitrary position is formed in an approximate bag shape with an openend, and the open end is heat-sealed after filling the contents throughthe open end. As a result, the packaging bag 1 filled with the contentsis completed. When the packaging bag 1 of the present embodiment filledwith the contents is put into the microwave and heated, moisturecontained in the contents becomes water vapor. Accordingly, thepackaging bag 1 expands, and the internal pressure of the packaging bag1 is increased.

Due to the increase in internal pressure, a crack is generated in thefragile processed portion, and a hole passing through the laminated filmin the thickness direction is formed. The inventors of the inventionhave found out that, if the Young's modulus of the fragile processedportion 40 defined as described above is set to be less than thepredetermined value described above, the entire fragile processedportion 40 does not tear when the internal pressure of the packaging bag1 is increased during the heating by the microwave and a plurality ofsmall holes 41 spaced apart from each other are formed as shown in FIG.4.

Basically, the fragile processed portion 40 is easily deformed in thelongitudinal direction, but is difficult to deform in a directionperpendicular to the longitudinal direction because the fragileprocessed portion 40 is close to a portion bonded to the outer layer 20.It is thought that this is because the stress concentrates on somepoints spaced apart from each other in the fragile processed portion 40.It is thought that the reason why the crack does not spread so as toconnect the formed small holes 41 to each other is that water vapor isdischarged through the small holes 41 and accordingly the internalpressure is reduced.

In addition, the inventors have found out that, if the fragile processedportion 40 is formed by laser processing, a number of small holes 41 areformed at relatively short equal distances in the longitudinal directionof the fragile processed portion 40. Presumably, this is because a deepportion and a shallow portion are repeatedly formed in a groove by aperiodic variation in the output of laser light when forming the fragileprocessed portion and the deep portion of the groove, that is, a thinnerportion in the fragile processed portion tears early and accordingly asmall hole is formed.

In addition, when the inner layer 30 is formed of LLDPE, the inner layer30 can stand the internal pressure applied to the laminated film evenafter the small holes 41 are formed because the LLDPE extends easily dueto its high flexibility and also has high impact strength. Therefore, itis possible to prevent the inner layer 30 from being broken due to smallholes communicating with each other.

Since a plurality of small holes 41 are formed in the fragile processedportion 40, water vapor generated inside the packaging bag 1 is notdischarged at once to the outside of the packaging bag 1, but continuesto be discharged to such an extent as to prevent rupture in response toan increase in internal pressure. Thus, it is possible to cause norupture or the like during the heating by the microwave and toappropriately perform steaming with water vapor remaining in thepackaging bag 1.

As described above, according to the packaging bag 1 configured toinclude the laminated film 10 of the present embodiment, a plurality ofsmall holes 41 are formed in the fragile processed portion 40 during theheating by the microwave. Therefore, it is possible to appropriatelyperform steaming by keeping a portion of water vapor in the packagingbag while appropriately preventing rupture or the like due to theincrease in internal pressure.

If the fragile processed portion 40 is provided, processes such asre-fusing after cutting the inner layer with a slit is not required. Forthis reason, it is possible to simplify the process of manufacturing thelaminated film 10. Therefore, it is possible to easily manufacture thepackaging bag 1.

In addition, since the fragile processed portion 40 can be formedanywhere on the laminated film except for the ends where the inner layer30 is heat-sealed, the degree of freedom in the packaging bag design ishigh. Accordingly, even when manufacturing a plurality of types ofpackaging bags in which the position of the fragile processed portiondiffers depending on the type of contents or the like, it is possible toeasily correspond to the situation, for example, by changing the laserradiation position.

In the present embodiment, each of the outer layer and the inner layermay not necessarily be a single layer. In a laminated film 10A in amodification example shown in FIG. 5A, an outer layer 20A has a firstlayer 21 formed of a first resin and a second layer 22 formed of asecond resin that is different from the first resin.

In a laminated film 10B in a modification example shown in FIG. 5B, aninner layer 30A bonded to the outer layer 20A has an upper layer 31formed of a third resin and a lower layer 32 formed of a fourth resinthat is different from the third resin. For example, when LLDPE is usedas the inner layer 30A, it is preferable that the inner layer 30A hasthe upper layer 31 formed of LLDPE and the lower layer 32 formed ofLLDPE having different physical properties from the upper layer 31. Inthe configuration shown in FIG. 5B, the laminated film 10B can be formedwithout using an adhesive layer by bonding the outer layer 20A and thelower layer 32 to each other with a third resin using a sandwichlamination method.

In addition, the number of layers and the configuration of layers arenot limited as long as the fragile processed portion can be formed. Forexample, it is possible to form an inner layer having two layers and anouter layer having a single layer, or it is possible to form an innerlayer having three or more layers and an outer layer having three ormore layers.

In the embodiment of the invention, it is preferable that the laminationstrength under the heating environment near the fragile processedportion is equal to or greater than 0.1 N/25 mm. If the laminationstrength under the heating environment is equal to or greater than 0.1N/25 mm, even when the internal volume of the packaging material expandsduring microwave heating, stress due to volume expansion is limited tothe inner layer of the fragile processed region because the outer layerand the inner layer are bonded to each other in a region other than thefragile processed portion. Therefore, since the inner layer of theregion is efficiently extended and breakage occurs locally, a vapordischarge hole can be made to appear only in the fragile processedregion.

On the other hand, if the lamination strength under the heatingenvironment is less than 0.1 N/25 mm, when the internal volume of thepackaging material expands during microwave heating, the outer layer andthe inner layer are peeled off from each other due to the stress bywhich the inner layer is extended. Accordingly, the inner layer extendsendlessly as a single layer. If the internal volume is excessivelyincreased, the strength of the inner layer is reduced, and breakageoccurs from the unspecified location.

A laminated film and a packaging bag according to a second embodiment ofthe invention will be described with reference to FIGS. 6A to 7C. Alaminated film 51 of the present embodiment and the laminated film 10that forms the packaging bag 1 of the first embodiment are different inthat an intermediate layer is provided between the outer layer and theinner layer in the second embodiment. In the following explanation, thesame components as those already described are denoted by the samereference numerals, and repeated explanation thereof will be omitted.

Also in the present embodiment, the Young's modulus of the fragileprocessed portion 40 is equal to or less than 2.0 gigapascals (GPa) inthe measurement conforming to JISK7127. Also in the present embodiment,in particular, when using the linear low density polyethylene (LLDPE) asa resin for forming the inner layer 30, the Young's modulus of thefragile processed portion 40 is less than 2.8 gigapascals (GPa) in themeasurement conforming to JISK7127. In addition, also in the embodimentof the invention, it is preferable that the lamination strength underthe heating environment near the fragile processed portion is equal toor greater than 0.1 N/25 mm.

FIG. 6A is a partial plan view of the laminated film 51 of the presentembodiment, and FIG. 6B is a cross-sectional view taken along the lineB-B of FIG. 6A. As shown in FIG. 6B, in the laminated film 51, an inklayer (intermediate layer) 52 is formed between the outer layer 20 andthe inner layer 30.

The ink layer 52 is provided in order to improve the design of thepackaging container or to provide functions, such as various kinds ofdisplay regarding products, and can be formed using various kinds ofknown inks.

Generally, the lamination strength between the outer layer 20 and theinner layer 30 is reduced by interposing the ink layer 52. If thelamination strength of the fragile processed portion 40 and thelamination strength around the fragile processed portion 40 are reduced,small holes may not be formed well at the time of heating. In order toprevent this, in the present embodiment, as shown in FIG. 6A, the inklayer 52 is not formed in the fragile processed portion and around thefragile processed portion. A range where the ink layer 52 is not formedaround the fragile processed portion 40 can be appropriately set. Forexample, it is possible to set a rectangular range including positionsaway from both sides of the fragile processed portion 40 in thelongitudinal direction by 5 mm and positions away from both sides of thefragile processed portion 40 in the width direction by 2.5 mm.

When the lamination strength between the outer layer and the inner layeris not high due to compatibility of materials, it is possible to improvethe lamination strength by providing an intermediate layer. FIGS. 7A to7C shows modification examples for increasing the lamination strengthbetween the outer layer and the inner layer.

FIGS. 7A to 7C are partial plan views when the outer layer is removedfrom the laminated film in all of the modification examples. On asurface of the inner layer 55 bonded to the outer layer, a stronglamination layer 56 is formed by applying a medium. In addition, thelamination strength between the outer layer and the inner layer in aportion where the strong lamination layer 56 is formed is more improvedthan that in other portions. As shown in FIG. 7A, when the stronglamination layer 56 is formed on both sides of the fragile processedportion 40 in the longitudinal direction (shown by the dotted line sincethe fragile processed portion is mainly formed in the outer layer),stress applied to the fragile processed portion 40 becomes uneven due tothe strong lamination layer 56, and the small hole 41 is formed in aportion P where the extension line of the fragile processed portion 40and the strong lamination layer 56 cross each other.

Accordingly, the strong lamination layer (intermediate layer) 56 in thismodification example is preferably formed on at least both sides of thefragile processed portion 40 in the longitudinal direction. As long asthis condition is satisfied, the strong lamination layer (intermediatelayer) 56 may be formed in the entire periphery of the fragile processedportion 40 as shown in FIG. 7B, or the strong lamination layer(intermediate layer) 56 may be formed so as to entirely cover both sidesof the fragile processed portion 40 in the longitudinal direction asshown in FIG. 7C. In addition, although not shown, the strong laminationlayer may be formed on the entire surface of the laminated film.

Also in the laminated film 51 of the present embodiment, similar to thelaminated film 10 of the first embodiment, it is possible toappropriately perform steaming while appropriately preventing rupture orthe like due to the increase in internal pressure while being heated bythe microwave.

In addition, since the intermediate layer is provided between the outerlayer and the inner layer, even if various materials are used for theouter layer and the inner layer, it is possible to appropriately formsmall holes in the fragile processed portion while being heated byappropriately adjusting the lamination strength of the fragile processedportion and the lamination strength around the fragile processedportion.

In addition, granting the design for the packaging bag formed by thelaminated film or displaying product information or the like can beeasily performed by forming the intermediate layer as an ink layer.

Subsequently, the invention will be further described with reference toexamples.

Example 1 Group

In Example 1 group, each of the outer layer and the inner layer isformed as a single layer.

Example 1-1

A PET film having a thickness of 12 μm was used as an outer layer, andan LLDPE film (Young's modulus of 0.15 GPa: measured according toJISK7127, the same hereinbelow) having a thickness of 30 μm was used asan inner layer. The outer layer and the inner layer were bonded to eachother by dry lamination using an aliphatic ester based adhesive for drylamination, and a fragile processed portion having a depth approximatelypassing through the outer layer was formed in a width of 150 μm and alength of 40 mm by laser irradiation, thereby manufacturing a laminatedfilm of Example 1-1.

In the laminated film of Example 1-1, the Young's modulus of the fragileprocessed portion measured by the above-described method was 1.6 GPa,and the lamination strength (measured according to JISK6854) between theouter layer and the inner layer was 8 N/25 mm.

This was formed in a bag shape using the above-described method, therebymanufacturing the packaging bag of the present example. Since thepackaging bag was formed in an approximately rectangular parallelepipedshape, a surface including a bonding portion between the end 10 a andthe end 10 b was set as a bottom surface, the opposite surface was setas a top surface, and a surface between the top and bottom surfaces wasset as a side surface. The packaging bag of Example 1-1 was formed suchthat the fragile processed portion was located on the top surface.

Example 1-2

The same laminated film as in Example 1-1 was used as a laminated film.The packaging bag of Example 1-2 was formed such that the fragileprocessed portion was located on the side surface.

Example 1-3

The same laminated film as in Example 1-1 was used as a laminated film.The packaging bag of Example 1-2 was formed such that the fragileprocessed portion was located on the bottom surface.

Example 1-4

Materials of the outer layer and the inner layer were the same as thosein Example 1-1. The fragile processed portion was formed in a brokenline shape by laser irradiation. A dotted line was formed by repeatedlyforming a groove having a length of 1 mm 30 times with a distance of 0.1mm therebetween. The Young's modulus of the fragile processed portionwas 1.6 GPa.

The packaging bag of Example 1-4 was formed such that the fragileprocessed portion was located on the top surface.

Example 1-5

Except that an LLDPE film (Young's modulus of 0.15 GPa) having athickness of 40 μm was used as an inner layer, the laminated film andthe packaging bag were manufactured in the same procedure as in Example1-1. The Young's modulus of the fragile processed portion was 1.7 GPa,and the lamination strength between the outer layer and the inner layerwas 8 N/25 mm.

Example 1-6

Except that an LLDPE film (Young's modulus of 0.12 GPa) having athickness of 30 μm was used as an inner layer, the laminated film andthe packaging bag were manufactured in the same procedure as in Example1-1. The Young's modulus of the fragile processed portion was 1.6 GPa,and the lamination strength between the outer layer and the inner layerwas 8 N/25 mm.

Example 1-7

Except that an LLDPE film (Young's modulus of 0.05 GPa) having athickness of 30 μm was used as an inner layer, the laminated film andthe packaging bag were manufactured in the same procedure as in Example1-1. The Young's modulus of the fragile processed portion was 1.0 GPa,and the lamination strength between the outer layer and the inner layerwas 8 N/25 mm.

Example 1-8

Except that an EVA film (Young's modulus of 0.16 GPa) having a thicknessof 30 μm was used as an inner layer, the laminated film and thepackaging bag were manufactured in the same procedure as in Example 1-1.The Young's modulus of the fragile processed portion was 1.7 GPa, andthe lamination strength between the outer layer and the inner layer was8 N/25 mm.

Example 1-9

Except that an LDPE film (Young's modulus of 0.3 GPa) having a thicknessof 30 μm was used as an inner layer, the laminated film and thepackaging bag were manufactured in the same procedure as in Example 1-1.The Young's modulus of the fragile processed portion was 2.0 GPa, andthe lamination strength between the outer layer and the inner layer was8 N/25 mm.

Comparative Example 1-A

Except that a CPP film (Young's modulus of 0.7 GPa) having a thicknessof 30 μm was used as an inner layer, the laminated film and thepackaging bag were manufactured in the same procedure as in Example 1-1.The Young's modulus of the fragile processed portion was 2.2 GPa, andthe lamination strength between the outer layer and the inner layer was8 N/25 mm.

Comparative Example 1-B

Except that a CPP film (Young's modulus of 0.8 GPa) having a thicknessof 30 μm was used as an inner layer, the laminated film and thepackaging bag were manufactured in the same procedure as in Example 1-1.The Young's modulus of the fragile processed portion was 2.5 GPa, andthe lamination strength between the outer layer and the inner layer was8 N/25 mm.

For the packaging bags of the examples and the comparative examplesdescribed above, a heating experiment using a microwave was performedaccording to the following procedure.

At the time of packaging bag formation, a cloth that was frozen in astate containing 50-cc water was disposed as contents in a packagingbag, and then the ends of the packaging bag was closed for sealing. Thepackaging bag containing the contents was heated for two minutes at 600watts output using a microwave, and the occurrence of rupture and thestate of steaming were observed. The rupture was defined as either astate where a portion other than a fragile processed portion in apackaging bag tore or a state where the fragile processed portion torebut a crack extended to a portion other than the fragile processedportion. For the steaming, “steam holes having a diameter of mm unit or1 mm or less were formed in the fragile processed portion during heatingand the expanded state was held satisfactorily” was set as excellent,“steam holes having a diameter of cm unit were formed in the fragileprocessed portion during heating and the expanded state was held to someextent” was set as passing, and “portions other than the fragileprocessed portion tore or the fragile processed portion tore but thecrack extended to a portion other than the fragile processed portion andaccordingly it was not possible to hold the expanded state” was set asfailing. Table 1 shows the results of Examples 1-1 to 1-8 andComparative examples 1-A to 1-C.

TABLE 1 Fragile processed Inner layer portion Young's Young's Fragilemodulus modulus Lamination processed portion Microwave heating MaterialThickness (Gpa) (Gpa) strength Shape Position Rupture Steaming StateExample 1-1 LLDPE 30 0.15 1.6 8N Continuous Top None Excellent Pluralityof small holes in line surface processed portion Example 1-2 LLDPE 300.15 1.6 8N Continuous Side None Excellent Plurality of small holes inline surface processed portion Example 1-3 LLDPE 30 0.15 1.6 8NContinuous Bottom None Excellent Plurality of small holes in linesurface processed portion Example 1-4 LLDPE 30 0.15 1.6 8N Broken TopNone Excellent Plurality of small holes in line surface processedportion Example 1-5 LLDPE 40 0.15 1.7 8N Continuous Top None ExcellentPlurality of small holes in line surface processed portion Example 1-6LLDPE 30 0.12 1.6 8N Continuous Top None Excellent Plurality of smallholes in line surface processed portion Example 1-7 LLDPE 30 0.16 1.7 8NContinuous Top None Excellent Plurality of small holes in line surfaceprocessed portion Example 1-8 EVA 30 0.05 1.0 8N Continuous Top NoneExcellent Plurality of small holes in line surface processed portionExample 1-9 LLDPE 30 0.3 2.0 8N Continuous Top None Passing Processedportion was line surface largely opened Comparative CPP 30 0.7 2.2 8NContinuous Top Occurred Failing Torn from processed Example 1-A linesurface portion Comparative CPP 30 0.8 2.5 8N Continuous Top OccurredFailing Sealed portion was torn example 1-B line surface

As shown in Table 1, in Examples 1-1 to 1-8 in which the Young's modulusof the fragile processed portion was set to 2.0 GPa or less, a pluralityof small holes were formed in the fragile processed portion duringheating, and vapor was discharged to the outside of the packaging bagwithout causing rupture. In addition, since the expanded state of thepackaging bag was held, it was possible to perform steaming. Also inExample 1-9, since a large crack was formed over the entire fragileprocessed portion, it was possible to suppress the rupture.

In contrast, in Comparative examples 1-A and 1-B, rupture was startedfrom the fragile processed portion and the heat-sealed end of thelaminated film.

Example 2 Group

Example 2 group is examples in which at least one of the outer layer andthe inner layer is formed so as to have a plurality of layers.

Example 2-1

A PET film having a thickness of 12 μm and an ONy film having athickness of 15 μm were used as an outer layer, and an LLDPE film(Young's modulus of 0.15 GPa) having a thickness of 40 μm was used as aninner layer.

The PET film and the ONy film and the outer layer and the inner layerwere bonded to each other by dry lamination using an aliphatic esterbased adhesive for dry lamination, and a fragile processed portionhaving a depth approximately passing through the outer layer was formedin a width of 150 μm and a length of 40 mm by laser irradiation, therebymanufacturing a laminated film of Example 2-1. In the laminated film ofExample 2-1, the Young's modulus of the fragile processed portion was1.6 GPa, and the lamination strength between the outer layer and theinner layer was 8 N/25 mm.

The laminated film of Example 2-1 was formed in a bag shape using thesame method as in Example 1-1, thereby manufacturing the packaging bagof the present example.

Example 2-2

The configuration of the outer layer was the same as that in Example2-1, and an LLDPE film having a thickness of 40 μm was prepared as aninner layer.

The films of the outer layer were bonded to each other by drylamination, and then the outer layer and the inner layer were bonded toeach other by performing sandwich lamination using the LDPE as a sandlayer. Thus, a laminated film (the Young's modulus of the inner layerwas 0.15 GPa) of Example 2-2 having a two-layer configuration in whichthe inner layer included the LDPE (13 μm in thickness) and the LLDPE wasmanufactured. In the laminated film of Example 2-2, the Young's modulusof the fragile processed portion was 1.6 GPa, and the laminationstrength between the outer layer and the inner layer was 8 N/25 mm.

The laminated film of Example 2-1 was formed in a bag shape using thesame method as in Example 1-1, thereby manufacturing the packaging bagof the present example.

Comparative Example 2-A

Except that the depth of the fragile processed portion was set to adepth approximately passing through only the PET film, the laminatedfilm of Comparative example 2-A was manufactured in the same procedureas in Example 2-1. In the laminated film of Comparative example 2-A, theYoung's modulus of the fragile processed portion was 3.5 GPa, and thelamination strength between the outer layer and the inner layer was 8N/25 mm.

The laminated film of Comparative example 2-A was formed in a bag shapeusing the same method as in Example 1-1, thereby manufacturing thepackaging bag of the present comparative example.

Comparative Example 2-B

Except that the depth of the fragile processed portion was set to adepth reaching an intermediate portion of the ONy film in the thicknessdirection, the laminated film of Comparative example 2-B wasmanufactured in the same procedure as in Example 2-1. In the laminatedfilm of Comparative example 2-B, the Young's modulus of the fragileprocessed portion was 3.1 GPa, and the lamination strength between theouter layer and the inner layer was 8 N/25 mm.

The laminated film of Comparative example 2-B was formed in a bag shapeusing the same method as in Example 1-1, thereby manufacturing thepackaging bag of the present comparative example.

Table 2 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 1 group for thepackaging bags of Examples 2-1 to 2-2 and Comparative examples 2-A and2-B.

TABLE 2 Young's Young's modulus of Lamination Fragile processed portionmodulus of fragile processed Lamination Microwave heating method DepthShape Position inner layer portion strength Rupture Steaming StateExample 2-1 Dry Passing Contin- Top 0.15 1.6 8N None Excellent Pluralityof lamination through uous surface small holes outer line in processedlayer portion Example 2-2 Sandwich Passing Contin- Top 0.15 1.6 8N NoneExcellent Plurality of lamination through uous surface small holes outerline in processed layer portion Comparative Dry Depth Contin- Top 0.153.5 8N Occurred Failing Sealed example 2-A lamination reaching uoussurface portion between line was torn layers of PET Comparative DryDepth Contin- Top 0.15 3.1 8N Occurred Failing Sealed example 2-Blamination reaching uous surface portion between line was torn layers ofONy

As shown in Table 2, in Examples 2-1 to 2-2 in which the Young's modulusof the fragile processed portion was set to 2.0 GPa or less, a pluralityof small holes were formed in the fragile processed portion duringheating, and vapor was discharged to the outside of the packaging bagwithout causing rupture. In addition, since the expanded state of thepackaging bag was held, it was possible to perform steaming.

In contrast, in Comparative examples, rupture was started from theheat-sealed end of the laminated film.

Example 3 Group

Example 3 group is examples in which an ink layer for reducing thelamination strength is provided as an intermediate layer.

Example 3-1

A PET film having a thickness of 12 μm was used as an outer layer, andan LLDPE film (Young's modulus of 0.15 GPa) having a thickness of 30 μmwas used as an inner layer. An ink layer was formed on one surface ofthe PET film except for a rectangular region of 50 mm×5 mm by printingusing white ink. Then, the surface of the outer layer on which the inklayer was provided and the inner layer were bonded to each other by drylamination using an aliphatic ester based adhesive for dry lamination.Then, a fragile processed portion having a depth approximately passingthrough the outer layer was formed in a width of 150 μm and a length of40 mm so as to be located in a region where no ink layer was formed inplanar view, thereby manufacturing the laminated film of Example 3-1. Inthe laminated film of Example 3-1, the Young's modulus of the fragileprocessed portion was 1.6 GPa, and the lamination strength between theouter layer and the inner layer was 8 N/25 mm.

The laminated film of Example 3-1 was formed in a bag shape using thesame method as in Example 1-1, thereby manufacturing the packaging bagof the present example.

Example 3-2

Except that an LLDPE film (Young's modulus of 0.15 GPa) having athickness of 40 μm was used as an inner layer, the laminated film andthe packaging bag were manufactured in the same procedure as in Example3-1. The Young's modulus of the fragile processed portion was 1.6 GPa,and the lamination strength between the outer layer and the inner layerwas 8 N/25 mm.

Example 3-3

Except that the shape of the fragile processed portion was the same asthat in Example 1-4, the laminated film and the packaging bag weremanufactured in the same procedure as in Example 3-1. The Young'smodulus of the fragile processed portion was 1.6 GPa, and the laminationstrength between the outer layer and the inner layer was 8 N/25 mm.

Example 3-4

Except that the ink layer was formed on one entire surface of the PETfilm, the laminated film and the packaging bag were manufactured in thesame procedure as in Example 3-1. The Young's modulus of the fragileprocessed portion was 1.6 GPa, and the lamination strength between theouter layer and the inner layer was 1.8 N/25 mm.

Table 3 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 1 group for thepackaging bags of Examples 3-1 to 3-4.

TABLE 3 Fragile Young's processed portion modulus Lamination Ink Young'sof fragile strength of Inner layer lamination modulus of processedprocessed Microwave heating Material Thickness Shape pattern inner layerportion portion Rupture Steaming State Example 3-1 LLDPE 30 ContinuousWindow around 0.15 1.6 8N None Excellent Plurality of line fragileprocessed small holes portion is in processed excluded portion Example3-2 LLDPE 40 Continuous Window around 0.15 1.6 8N None ExcellentPlurality of line fragile processed small holes portion is in processedexcluded portion Example 3-3 LLDPE 30 Broken Window around 0.15 1.6 8NNone Excellent Plurality of line fragile processed small holes portionis in processed excluded portion Example 3-3 LLDPE 30 Continuous Entire0.15 1.6 2.5 to None Excellent Vapor was ejected line surface 3N sincethe number coated of small holes was small

As shown in Table 3, in Examples 3-1 to 3-3 in which the Young's modulusof the fragile processed portion was set to 2.0 GPa or less and no inklayer was formed around the fragile processed portion, a plurality ofsmall holes were formed in the fragile processed portion during heating,and vapor was discharged to the outside of the packaging bag withoutcausing rupture. In addition, since the expanded state of the packagingbag was held, it was possible to perform steaming.

On the other hand, although it was also possible to perform steamingwhile suppressing the rupture in the example 3-4, a phenomenon thatvapor was ejected from the packaging bag was observed since the numberof small holes formed in the fragile processed portion was smaller thanthat in the other examples. Accordingly, when providing the ink layer,it was preferable to avoid the periphery of the fragile processedportion.

Example 4 Group

Example 4 group is examples in which a strong lamination layer forincreasing the lamination strength is provided as an intermediate layer.

Example 4-1

A PET film having a thickness of 12 μm was used as an outer layer, andan LLDPE film (Young's modulus of 0.16 GPa) having a thickness of 40 μmwas used as an inner layer. In addition, a medium coat layer (stronglamination layer) of 10 mm×5 mm was formed on both sides of a region forforming the fragile processed portion in the longitudinal direction, onone surface of the outer layer, by printing. The surface of the outerlayer on which the medium coat layer was provided and the inner layerwere bonded to each other by dry lamination using an aliphatic esterbased adhesive for dry lamination. Then, a fragile processed portionhaving a depth approximately passing through the outer layer was formedin a width of 150 μm and a length of 40 mm so as to be located betweentwo medium coat layers in planar view, thereby manufacturing thelaminated film of Example 4-1. In the laminated film of Example 4-1, theYoung's modulus of the fragile processed portion was 1.6 GPa, and thelamination strength between the outer layer and the inner layer in themedium coat layer was 5 N/25 mm.

The laminated film of Example 4-1 was formed in a bag shape using thesame method as in Example 1-1, thereby manufacturing the packaging bagof the present example.

Example 4-2

Except that the medium coat layer was formed on the entire surface ofthe PET film (outer layer) excluding a non-formation region of 50 mm×5mm and the fragile processed portion was formed so as to be located inthe non-formation region in planar view, the laminated film and thepackaging bag were manufactured in the same procedure as in Example 4-1.The Young's modulus of the fragile processed portion was 1.6 GPa, andthe lamination strength between the outer layer and the inner layer inthe medium coat layer was 5 N/25 mm.

Example 4-3

Except that the medium coat layer was formed on the entire surface ofthe PET film excluding a non-formation region, which is formed with awidth of 50 mm from one end to the other end in the width direction ofthe PET film, and the fragile processed portion was formed so as to belocated in the non-formation region in planar view, the laminated filmand the packaging bag were manufactured in the same procedure as inExample 4-1. The Young's modulus of the fragile processed portion was1.6 GPa, and the lamination strength between the outer layer and theinner layer in the medium coat layer was 5 N/25 mm.

Example 4-4

Except that the shape of the fragile processed portion was the same asthat in Example 1-4, the laminated film and the packaging bag weremanufactured in the same procedure as in Example 4-1. The Young'smodulus of the fragile processed portion was 1.6 GPa, and the laminationstrength between the outer layer and the inner layer in the medium coatlayer was 5 N/25 mm.

Example 4-5

Except that no medium coat layer was provided, the laminated film andthe packaging bag were manufactured in the same procedure as in Example4-1. The Young's modulus of the fragile processed portion was 1.6 GPa,and the lamination strength between the outer layer and the inner layerwas 2 N/25 mm.

Table 4 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 1 group for thepackaging bags of Examples 4-1 to 4-5.

TABLE 4 Fragile Young's processed portion modulus Lamination MediumYoung's of fragile strength of Inner layer coat modulus of processedprocessed Microwave heating Material Thickness Shape layer inner layerportion portion Rupture Steaming State Example 4-1 LLDPE 40 ContinuousBoth sides 0.15 1.6 5N None Excellent Small hole at intersection line ofprocessed between extension line of portion processed portion and mediumcoat layer Example 4-2 LLDPE 40 Continuous Window around 0.15 1.6 5NNone Excellent Small hole at intersection line fragile processed betweenextension line of portion is processed portion and excluded medium coatlayer Example 4-3 LLDPE 40 Continuous Strip shape on 0.15 1.6 5N NoneExcellent Small hole at intersection line both sides of betweenextension line of processed portion processed portion and medium coatlayer Example 4-4 LLDPE 40 Broken Both sides 0.15 1.6 5N None ExcellentSmall hole at intersection line of processed between extension line ofportion processed portion and medium coat layer Example 4-5 LLDPE 40Continuous No coating 0.15 1.6 2N None Passing Processed portion wasline largely opened

As shown in Table 4, in Examples 4-1 to 4-4 in which the Young's modulusof the fragile processed portion was set to 2.0 GPa or less and themedium coat layer was provided on both sides of the fragile processedportion in the longitudinal direction, a small hole was formed at theintersection (two places) between the extension line of the fragileprocessed portion and the medium coat layer during heating, and vaporwas discharged to the outside of the packaging bag without causingrupture. In addition, since the expanded state of the packaging bag washeld, it was possible to perform steaming.

In Example 4-5 in which no medium coat layer was provided, since a largecrack was formed over the entire fragile processed portion, it waspossible to suppress the rupture.

Example 5 Group

In Example 5 group, each of the outer layer and the inner layer isformed as a single layer.

In Examples 5-1 to 5-3, a PET film having a thickness of 12 μm was usedas an outer layer, and an LLDPE film having a thickness of 30 μm or 40μm was used as an inner layer. The outer layer and the inner layer werebonded to each other by dry lamination using an aliphatic ester basedadhesive for dry lamination, and a fragile processed portion having adepth approximately passing through the outer layer was formed in awidth of 150 μm and a length of 40 mm by laser irradiation, therebymanufacturing a laminated film.

In Examples 5-4 to 5-6, a PET film having a thickness of 16 μm was usedas an outer layer, and an LLDPE film having a thickness of 30 μm or 40μm was used as an inner layer. Then, the PET film and the LLDPE filmwere bonded to each other using the same method. In Examples 5-1 to 5-6,the Young's modulus of the fragile processed portion was in the range of1.8 GPa to 2.0 GPa.

In Example 5-7, a PET film having a thickness of 12 μm was used as anouter layer, and a low density polyethylene (LDPE) film (having athickness of 40 μm) was used as an inner layer. In Example 5-7, theYoung's modulus of the fragile processed portion was 2.0 GPa.

In Comparative examples 5-A and 5-B, a PET film having a thickness of 12μm was used as an outer layer, and an unstretched polypropylene (CPP)film (having a thickness of 40 μm) was used as an inner layer. TheYoung's modulus of the fragile processed portion in Comparative example5-A was 2.2 GPa, and the Young's modulus of the fragile processedportion in Comparative example 5-B was 2.5 GPa.

Each film of the examples and comparative examples was formed in a bagshape, thereby forming a packaging bag.

For the packaging bags of the examples and the comparative examplesdescribed above, a heating experiment using a microwave was performedaccording to the following procedure.

At the time of packaging bag formation, a cloth that was frozen in astate containing 50-cc water was disposed as contents in a packagingbag, and then the ends of the packaging bag was closed for sealing. Thepackaging bag containing the contents was heated for two minutes at 600watts output using a microwave, and the occurrence of rupture and thestate of steaming were observed. Table 5 shows the results of Examples5-1 to 5-7 and Comparative examples 5-A and 5-B.

TABLE 5 Young's Inner layer modulus Outer layer Impact of fragileThickness Thickness fracture processed Microwave heating Material (μm)Material (μm) mass (g) portion Rupture Steaming State Example 5-1 PET 12LLDPE 40 640 1.8 None Excellent Plurality of small holes in processedportion Example 5-2 PET 12 LLDPE 40 627 1.6 None Excellent Plurality ofsmall holes in processed portion Example 5-3 PET 12 LLDPE 30 536 1.6None Excellent Plurality of small holes in processed portion Example 5-4PET 16 LLDPE 40 640 2.0 None Excellent Plurality of small holes inprocessed portion Example 5-5 PET 16 LLDPE 40 627 2.0 None ExcellentPlurality of small holes in processed portion Example 5-6 PET 16 LLDPE30 536 2.0 None Excellent Plurality of small holes in processed portionExample 5-7 PET 12 LLDPE 40 64 2.0 None Passing Processed portion waslargely opened Comparative PET 12 CPP 40 54 2.2 Occurred Failing Tornfrom processed example 5-A portion Comparative PET 12 CPP 40 80 2.5Occurred Failing Sealed portion example 5-B was torn

As shown in Table 5, in the packaging bags of the examples, in Examples5-1 to 5-6 in which the LLDPE film was used as an inner layer, the innerlayer was extended easily, a plurality of small holes were formed in thefragile processed portion formed by laser irradiation, and vapor wasdischarged to the outside of the packaging bag without causing rupture.In addition, since the expanded state of the packaging bag was held, itwas possible to perform steaming appropriately. In Example 7 in whichLDPE was used to obtain 2.0 GPa as the Young's modulus of the fragileprocessed portion, the entire fragile processed portion was largelyopened to prevent the rupture.

In contrast, in the comparative examples, the resin for forming theinner layer was not LLDPE and accordingly the extension rate was low.For this reason, rupture was caused on the extension line of the fragileprocessed portion or at the heat-sealed end of the laminated film.

Example 6 Group

Example 6 group is examples in which at least one of the outer layer andthe inner layer is formed so as to have a plurality of layers.

Example 6-1

A PET film having a thickness of 12 μm and an ONy film having athickness of 15 μm were used as an outer layer, and an LLDPE film havinga thickness of 40 μm was used as an inner layer. The PET film and theONy film and the outer layer and the inner layer were bonded to eachother by dry lamination using an aliphatic ester based adhesive for drylamination, and a fragile processed portion having a depth approximatelypassing through the outer layer was formed in a width of 150 μm and alength of 40 mm by laser irradiation, thereby manufacturing a laminatedfilm of Example 6-1.

The laminated film of Example 6-1 was formed in a bag shape using thesame method as in Example 5-1, thereby manufacturing the packaging bagof the present example.

Example 6-2

The configuration of the outer layer and the inner layer was the same asthat in Example 6-1.

The films of the outer layer were bonded to each other by drylamination, and then the outer layer and the inner layer were bonded toeach other by performing sandwich lamination using the LDPE as a sandlayer. As a result, the laminated film of Example 6-2 in which the outerlayer and the inner layer were bonded to each other with an adhesivelayer (13 μm in thickness) formed of LDPE interposed therebetween wasmanufactured. The laminated film of Example 6-2 was formed in a bagshape using the same method as in Example 5-1, thereby manufacturing thepackaging bag of the present example.

In Examples 6-1 and 6-2, the Young's modulus of the fragile processedportion was 1.6 GPa.

Table 6 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 5 group for thepackaging bags of Examples 6-1 and 6-2.

TABLE 6 Fragile Inner layer processed Young's modulus Lamination Impactfracture portion of fragile Microwave heating method mass (g) Depthprocessed portion Rupture Steaming State Example 6-1 Dry 627 Passingthrough 1.6 None Excellent Plurality of small holes lamination outerlayer in processed portion Example 6-2 Sandwich 627 Passing through 1.6None Excellent Plurality of small holes lamination outer layer inprocessed portion

As shown in Table 6, in Examples 6-1 and 6-2, a plurality of small holeswere formed in the fragile processed portion during heating, and vaporwas discharged to the outside of the packaging bag without causingrupture. In addition, since the expanded state of the packaging bag washeld, it was possible to perform steaming.

Example 7 Group

Example 7 group is examples in which an ink layer for reducing thelamination strength is provided as an intermediate layer.

Example 7-1

A PET film having a thickness of 12 μm was used as an outer layer, andan LLDPE film having a thickness of 40 μm was used as an inner layer. Anink layer was formed on one surface of the PET film by printing usingwhite ink, but no ink layer was formed in an approximate strip regionspreading in a width of 2.5 mm on four sides of the linear fragileprocessed portion (size and forming method are the same as those inExample 5-1). The surface of the outer layer on which the inner layerwas provided and the inner layer were bonded to each other by drylamination using an aliphatic ester based adhesive for dry laminationand the fragile processed portion was formed by laser irradiation,thereby manufacturing the laminated film of Example 7-1.

The laminated film of Example 7-1 was formed in a bag shape using thesame method as in Example 5-1, thereby manufacturing the packaging bagof the present example.

Example 7-2

Example 7-2 is different from Example 7-1 in that an LLDPE film having athickness of 30 μm is used. In addition, the shape of the fragileprocessed portion in planar view in Example 7-2 is different from thatin Example 7-1. The fragile processed portion was formed in a brokenline shape by laser irradiation. The broken line shape was formed byrepeatedly forming a groove having a length of 1 mm 30 times with adistance of 0.1 mm therebetween.

Examples 7-3 to 7-7

The only difference between Examples 7-3 to 7-7 and Example 7-1 is theshape of the fragile processed portion in planar view. FIGS. 8A to 8Eshow the shape of the fragile processed portion in planar view inExamples 7-3 to 7-7.

Example 7-8

Except that the ink layer was formed on one entire surface of the PETfilm (that is, except that there was no region where the ink layer wasnot formed), the laminated film and the packaging bag in Example 7-8were manufactured in the same procedure as in Example 7-1.

In Examples 7-1 to 7-8, the Young's modulus of the fragile processedportion was 1.6 GPa.

Table 7 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 5 group for thepackaging bags of Examples 7-1 to 7-8.

TABLE 7 Fragile Young's Inner layer processed portion modulus of ImpactInk fragile fracture lamination processed Microwave heating MaterialThickness mass (g) Shape pattern portion Rupture Steaming State Example7-1 LLDPE 40 627 Continuous Window around 1.6 None Excellent Pluralityof line fragile processed small holes portion is in processed excludedportion Example 7-2 LLDPE 30 627 Broken Window around 1.6 None ExcellentPlurality of line fragile processed small holes portion is in processedexcluded portion Example 7-3 LLDPE 40 627 8A Window around 1.6 NoneExcellent Plurality of fragile processed small holes portion is inprocessed excluded portion Example 7-4 LLDPE 40 627 8B Window around 1.6None Excellent Plurality of fragile processed small holes portion is inprocessed excluded portion Example 7-5 LLDPE 40 627 8C Window around 1.6None Excellent Plurality of fragile processed small holes portion is inprocessed excluded portion Example 7-6 LLDPE 40 627 8D Window around 1.6None Excellent Plurality of fragile processed small holes portion is inprocessed Good excluded portion Example 7-7 LLDPE 40 627 8E Windowaround 1.6 None Excellent Plurality of fragile processed small holesportion is in processed excluded portion Example 7-8 LLDPE 40 627Continuous Entire surface 1.6 None Excellent Vapor was ejected linecoated since the number of small holes was small

As shown in Table 7, in Examples 7-1 to 7-3 in which no ink layer wasformed around the fragile processed portion, a plurality of small holeswere formed in the fragile processed portion during heating, and vaporwas discharged to the outside of the packaging bag without causingrupture. In addition, since the expanded state of the packaging bag washeld, it was possible to perform steaming. In Examples 7-2 to 7-7, itbecame easy to distinguish the fragile processed portion from a scratch,a pinhole, or the like formed unintentionally in the manufacturingprocess of the packaging bag by forming the fragile processed portion ina characteristic shape instead of the mere linear shape. In Example 7-6,the test piece was manufactured in a shape shown by the dotted line ofFIG. 8D. However, it is thought that the same result is obtained if theintersection of the fragile processed portion is disposed near thecenter of the test piece.

On the other hand, although it was also possible to perform steamingwhile suppressing the rupture in the example 7-8, a phenomenon thatvapor was ejected from the packaging bag was observed since the numberof small holes formed in the fragile processed portion was smaller thanthat in the other examples. Accordingly, when providing the ink layer,it was preferable to avoid the periphery of the fragile processedportion.

Example 8 Group

Example 8 group is examples in which a strong lamination layer forincreasing the lamination strength is provided as an intermediate layer.

Example 8-1

A PET film having a thickness of 12 μm was used as an outer layer, andan LLDPE film having a thickness of 40 μm was used as an inner layer. Inaddition, a medium coat layer (strong lamination layer) of 10 mm×5 mmwas formed on both sides of a region for forming the fragile processedportion in the longitudinal direction, on one surface of the outerlayer, by printing. The surface of the outer layer on which the mediumcoat layer was provided and the inner layer were bonded to each other bydry lamination using an aliphatic ester based adhesive for drylamination. Then, by laser irradiation, a fragile processed portionhaving a depth approximately passing through the outer layer was formedin a width of 150 μm and a length of 40 mm so as to be located betweentwo medium coat layers in planar view, thereby manufacturing thelaminated film of Example 8-1. In the laminated film of Example 8-1, thelamination strength between the outer layer and the inner layer in themedium coat layer was 5 N/25 mm.

The laminated film of Example 8-1 was formed in a bag shape using thesame method as in Example 5-1, thereby manufacturing the packaging bagof the present example.

Example 8-2

Except that the medium coat layer was formed on the entire surface ofthe PET film excluding a non-formation region of 50 mm×5 mm and thefragile processed portion was formed so as to be located in thenon-formation region in planar view, the laminated film and thepackaging bag were manufactured in the same procedure as in Example 8-1.The lamination strength between the outer layer and the inner layer inthe medium coat layer was 5 N/25 mm.

Example 8-3

Except that the medium coat layer was formed on the entire surface ofthe PET film excluding a non-formation region, which is formed with awidth of 50 mm from one end to the other end in the width direction ofthe PET film, and the fragile processed portion was formed so as to belocated in the non-formation region in planar view, the laminated filmand the packaging bag were manufactured in the same procedure as inExample 8-1. The lamination strength between the outer layer and theinner layer in the medium coat layer was 5 N/25 mm.

Example 8-4

Except that the shape of the fragile processed portion was the same asthat in Example 7-2, the laminated film and the packaging bag weremanufactured in the same procedure as in Example 8-1. The laminationstrength between the outer layer and the inner layer in the medium coatlayer was 5 N/25 mm.

In Examples 8-1 to 8-4, the Young's modulus of the fragile processedportion was 1.6 GPa.

Table 8 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 5 group for thepackaging bags of Examples 8-1 to 8-4.

TABLE 8 Fragile Young's processed portion Lamination modulus Mediumstrength of of fragile Inner layer coat processed processed Microwaveheating Material Thickness Shape layer portion portion Rupture SteamingState Example 8-1 LLDPE 40 Continuous Both sides 5N 1.6 None ExcellentSmall hole at intersection line of processed between extension line ofportion processed portion and medium coat layer Example 8-2 LLDPE 40Continuous Window around 5N 1.6 None Excellent Small hole atintersection line fragile processed between extension line of portion isprocessed portion and excluded medium coat layer Example 8-3 LLDPE 40Continuous Strip shape on 5N 1.6 None Excellent Small hole atintersection line both sides of between extension line of processedportion processed portion and medium coat layer Example 8-4 LLDPE 40Dotted Both sides 5N 1.6 None Excellent Small hole at intersection lineof processed between extension line of portion processed portion andmedium coat layer

As shown in Table 8, in Examples 8-1 to 8-4 in which the medium coatlayer was provided on both sides of the fragile processed portion in thelongitudinal direction, a small hole was formed at the intersection (twoplaces) between the extension line of the fragile processed portion andthe medium coat layer during heating, and vapor was discharged to theoutside of the packaging bag without causing rupture. In addition, sincethe expanded state of the packaging bag was held, it was possible toperform steaming.

Example 9 Group

Example 9 group is examples in which an ink layer for reducing thelamination strength is provided as an intermediate layer.

Example 9-1

A PET film having a thickness of 12 μm was used as an outer layer, andan LLDPE film (Young's modulus of 0.15 GPa) having a thickness of 40 μmwas used as an inner layer. An ink layer was formed on one surface ofthe PET film except for a rectangular region of 50 mm×5 mm by printingusing ink. Then, the surface of the outer layer on which the ink layerwas provided and the inner layer were bonded to each other by drylamination using an aliphatic ester based adhesive for dry lamination.Then, by laser irradiation, a fragile processed portion having a depthapproximately passing through the outer layer was formed in a width of150 μm and a length of 40 mm so as to be located in a region where noink layer was formed in planar view, thereby manufacturing the laminatedfilm of Example 9-1. In the laminated film of Example 9-1, the Young'smodulus of the fragile processed portion was 1.6 GPa.

The laminated film of Example 9-1 was formed in a bag shape using thesame method as in Example 1-1, thereby manufacturing the packaging bagof the present example.

Example 9-2

Except that an LLDPE film having a Young's modulus of 0.27 GPa was usedas an inner layer, the laminated film and the packaging bag weremanufactured in the same procedure as in Example 9-1. The Young'smodulus of the fragile processed portion was 1.8 GPa.

Example 9-3

Except that a PET film having a thickness of 16 μm was used as an outerlayer, the laminated film and the packaging bag were manufactured in thesame procedure as in Example 9-1. The Young's modulus of the fragileprocessed portion was 2.0 GPa.

Example 9-4

Except that a PET film having a thickness of 25 μm was used as an outerlayer, the laminated film and the packaging bag were manufactured in thesame procedure as in Example 9-1. The Young's modulus of the fragileprocessed portion was 2.6 GPa.

Example 9-5

In Example 9-5, except that an LLDPE film having a thickness of 30 μmwas used as an inner layer and that the inner layer and the outer layerwere bonded to each other by applying an anchor coat (AC) agent formedof LDPE on the printing surface of the outer layer and performingextrusion lamination, the laminated film and the packaging bag weremanufactured in the same procedure as in Example 9-1. The thickness ofthe LDPE formed between the outer layer and the inner layer was 20 μm,and the Young's modulus of the fragile processed portion was 1.6 GPa.

Comparative Example 9-A

Except that a PET film having a thickness of 25 μm was used as an outerlayer and an LLDPE film having a Young's modulus of 0.45 GPa was used asan inner layer, the laminated film and the packaging bag weremanufactured in the same procedure as in Example 9-1. The Young'smodulus of the fragile processed portion was 2.8 GPa.

Table 9 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 5 group for thepackaging bags of Examples 9-1 to 9-5 and Comparative example 9-A.

TABLE 9 Young's Young's Fragile modulus modulus of Anchor processedportion of fragile Outer layer coat agent Inner layer Ink innerprocessed Thick- Thick- Thick- lumination layer portion Microwaveheating Material ness Material ness Material ness Shape pattern (GPa)(GPa) Rupture Steaming State Example PET 12 None LLDPE 40 Contin- Window0.15 1.6 None Excellent Plurality of 9-1 uous around small holes in linefragile processed processed portion portion is excluded Example 12 LLDPE40 Contin- Window 0.27 1.8 None Excellent Plurality of 9-2 uous aroundsmall holes in line fragile processed processed portion portion isexcluded Example 16 LLDPE 40 Contin- Window 0.15 2.0 None ExcellentPlurality of 9-3 uous around small holes in line fragile processedprocessed portion portion is excluded Example 25 LLDPE 40 Contin- Window0.15 2.6 None Excellent Plurality of 9-4 uous around small holes in linefragile processed processed portion portion is excluded Example 12 LDPE20 LLDPE 30 Contin- Window 0.15 1.6 None Excellent Plurality of 9-5 uousaround small holes in line fragile processed processed portion portionis excluded Com- 25 None LLDPE 40 Contin- Window 0.45 2.8 OccurredFailing Sealed portion parative uous around was torn exam- line fragileple processed 9-A portion is excluded

As shown in Table 9, in Examples 9-1 to 9-5 in which the Young's modulusof the fragile processed portion of the LLDPE film was set to be lessthan 2.8 GPa, a plurality of small holes were formed in the fragileprocessed portion during heating, and vapor was discharged to theoutside of the packaging bag without causing rupture. In addition, sincethe expanded state of the packaging bag was held, it was possible toperform steaming.

In contrast, in Comparative example 9-A, since the Young's modulus ofthe fragile processed portion was 2.8 or more, the seal portion causedrupture.

Example 10 Group

Example 10 group is examples regarding laminated films having variouslayer structures.

Example 10-1

A PET film having a thickness of 12 μm was used as an outer layer, andan LLDPE film (Young's modulus of 0.15 GPa) having a thickness of 40 μmwas used as an inner layer. The outer layer and the inner layer werebonded to each other by dry lamination using an aliphatic ester basedadhesive for dry lamination, and a fragile processed portion having adepth approximately passing through the outer layer was formed in awidth of 150 μm and a length of 40 μm by laser irradiation, therebymanufacturing a laminated film of Example 10-1.

In the laminated film of Example 10-1, the Young's modulus of thefragile processed portion measured by using the above-described methodwas 1.6 GPa. The lamination strength between the outer layer and theinner layer that was measured in a 80° C. environment after leaving thelaminated film in a 80° C. environment for two minutes was 3 N/25 mm.

Example 10-2

Except that an ink layer was formed on one surface of the PET filmexcluding a rectangular region of 50 mm×5 mm by printing using ink andthen the surface of the outer layer on which the ink layer was providedand the inner layer were bonded to each other by dry lamination using analiphatic ester based adhesive for dry lamination, the laminated filmand the packaging bag were manufactured in the same procedure as inExample 10-1.

In the laminated film of Example 10-2, the Young's modulus of thefragile processed portion was 1.6 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 1.2 N/25 mm.

Example 10-3

Except that the inner layer and the outer layer were bonded to eachother by applying an anchor coat (AC) agent formed of LDPE on theprinting surface of the outer layer and performing extrusion lamination,the laminated film and the packaging bag were manufactured in the sameprocedure as in Example 10-1.

In the laminated film of Example 10-3, the Young's modulus of thefragile processed portion was 1.6 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 2 N/25 mm.

Example 10-4

Except that an LLDPE film having a thickness of 30 μm was used as aninner layer and that heat-seal (HS) varnish was formed on one entiresurface of the PET film by printing using the HS varnish and then thesurface of the outer layer on which the ink layer was provided and theinner layer were bonded to each other by dry lamination using analiphatic ester based adhesive for dry lamination, the laminated filmand the packaging bag were manufactured in the same procedure as inExample 10-1.

In the laminated film of Example 10-4, the Young's modulus of thefragile processed portion was 1.6 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 0.05 N/25 mm.

Example 10-5

Except that an LDPE film (Young's modulus of 0.3 GPa) having a thicknessof 40 μm was used as an inner layer, the laminated film and thepackaging bag were manufactured in the same procedure as in Example10-1.

In the laminated film of Example 10-5, the Young's modulus of thefragile processed portion was 2.0 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 3 N/25 mm.

Comparative Example 10-A

Except that a CPP film (Young's modulus of 0.7 GPa) having a thicknessof 40 μm was used as an inner layer, the laminated film and thepackaging bag were manufactured in the same procedure as in Example10-1.

In the laminated film of Comparative example 10-A, the Young's modulusof the fragile processed portion was 2.5 GPa. The lamination strengthbetween the outer layer and the inner layer that was measured in a 80°C. environment after leaving the laminated film in a 80° C. environmentfor two minutes was 3 N/25 mm.

Example 10-6

Except that a PET film having a thickness of 16 μm was used as an outerlayer, the laminated film and the packaging bag were manufactured in thesame procedure as in Example 10-1.

In the laminated film of Example 10-6, the Young's modulus of thefragile processed portion was 2.2 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 3 N/25 mm.

Example 10-7

Except that a PET film having a thickness of 16 μm was used as an outerlayer and that HS varnish was formed on one entire surface of the PETfilm by printing using the HS varnish and then the surface of the outerlayer on which the ink layer was provided and the inner layer werebonded to each other by dry lamination using an aliphatic ester basedadhesive for dry lamination, the laminated film and the packaging bagwere manufactured in the same procedure as in Example 10-1.

In the laminated film of Example 10-7, the Young's modulus of thefragile processed portion was 2.2 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 0.05 N/25 mm.

Example 10-8

Except that a PET film having a thickness of 25 μm was used as an outerlayer and a CPP film having a Young's modulus of 0.27 GPa was used as aninner layer, the laminated film and the packaging bag were manufacturedusing the same procedure as in Example 10-1.

In the laminated film of Example 10-8, the Young's modulus of thefragile processed portion was 2.6 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 3 N/25 mm.

Example 10-9

Except that a PET film having a thickness of 25 μm was used as an outerlayer and a CPP film having a Young's modulus of 0.27 GPa was used as aninner layer and that HS varnish was formed on one entire surface of thePET film by printing using the HS varnish and then the surface of theouter layer on which the HS varnish layer was provided and the innerlayer were bonded to each other by dry lamination using an aliphaticester based adhesive for dry lamination, the laminated film and thepackaging bag were manufactured in the same procedure as in Example10-1.

In the laminated film of Example 10-9, the Young's modulus of thefragile processed portion was 2.6 GPa. The lamination strength betweenthe outer layer and the inner layer that was measured in a 80° C.environment after leaving the laminated film in a 80° C. environment fortwo minutes was 0.05 N/25 mm.

Comparative Example 10-B

Except that a PET film having a thickness of 25 μm was used as an outerlayer and a CPP film having a Young's modulus of 0.45 GPa was used as aninner layer, the laminated film and the packaging bag were manufacturedin the same procedure as in Example 10-1.

In the laminated film of Comparative example 10-B, the Young's modulusof the fragile processed portion was 2.8 GPa. The lamination strengthbetween the outer layer and the inner layer that was measured in a 80°C. environment after leaving the laminated film in a 80° C. environmentfor two minutes was 3 N/25 mm.

Table 10 shows the results of heating experiments using a microwave thatwere performed under the same conditions as in Example 5 group for thepackaging bags of Examples 10-1 to 10-9 and Comparative examples 10-Aand 10-B.

TABLE 10 Lamination strength between Young's inner layer and outer layermodulus of Lamination Young's fragile Outer layer Inner layer strengthunder modulus of processed Thick- Thick- Peeling heating inner layerportion Microwave heating Material ness Material ness interfaceenvironment (GPa) (GPa) Rupture Steaming State Example PET 12 LLDPE 40Adhesive 3N 0.15 1.6 None Excellent Plurality of 10-1 layer small holesin processed portion Example 12 LLDPE 40 Ink layer 1.2N 0.15 1.6 NoneExcellent Vapor was 10-2 ejected since the number of small holes wassmall Example 12 LLDPE 40 PET/AC 2N 0.15 1.6 None Excellent Plurality of10-3 interface small holes in processed portion Example 12 LLDPE 40 HSvarnish 0.05N 0.15 1.6 None Passing Processed 10-4 layer portion waslargely opened Example 12 LLDPE 40 Adhesive 3N 0.3 2.0 None PassingProcessed 10-5 layer portion was largely opened Compar- 12 CPP 40Adhesive 3N 0.7 2.5 Occurred Failing Sealed ative layer portion examplewas torn 10-A Example 16 LLDPE 40 Adhesive 3N 0.15 2.2 None ExcellentPlurality of 10-6 layer small holes in processed portion Example 16LLDPE 40 HS varnish 0.05N 0.15 2.2 None Passing Processed 10-7 layerportion was largely opened Example 25 LLDPE 40 Adhesive 3N 0.27 2.6 NoneExcellent Plurality of 10-8 layer small holes in processed portionExample 25 LLDPE 40 HS varnish 0.05N 0.27 2.6 None Passing Processed10-9 layer portion was largely opened Compar- 25 LLDPE 40 Adhesive 3N0.45 2.8 Occurred Failing Sealed ative layer portion example was torn10-B

As shown in Table 10, in Examples 10-1, 10-2, 10-3, 10-6, and 10-8 inwhich the Young's modulus of the fragile processed portion of the LLDPEfilm was set to be less than 2.8 GPa and the lamination strength was setto 0.1 N/25 mm or more, a plurality of small holes were formed in thefragile processed portion during heating, and vapor was discharged tothe outside of the packaging bag without causing rupture. In addition,since the expanded state of the packaging bag was held, it was possibleto perform steaming.

In Examples 10-4, 10-5, 10-7, and 10-9, the entire fragile processedportion was largely opened, and it was possible to prevent the rupture.

In contrast, in Comparative example 10-A, since the LLDPE film was notused as an inner layer and the Young's modulus of the fragile processedportion was larger than 2.0, the fragile processed portion tore to causerupture. In addition, in Comparative example 10-B, since the Young'smodulus of the fragile processed portion was 2.8 or more, the sealportion caused rupture.

While the embodiments and the examples of the invention have beendescribed, the technical scope of the invention is not limited to theabove embodiments, and it is possible to change the components invarious ways, or remove the components, or combine the components of theembodiments without departing from the scope of the invention.

For example, the laminated film of the invention is also available forpackaging containers other than the packaging bag. FIG. 9 shows anexample of a packaging container 101 in which the laminated film 10 isattached as a lid to a container body 100 formed of paper or the like.Also in this case, when heating the packaging container 101 in amicrowave, it is possible to perform steaming while appropriatelydischarging vapor from the fragile processed portion 40 so that ruptureor the like is prevented.

In addition, the laminated film of the invention may be manufactured ina roll shape by forming the fragile processed portion and then windingit using a so-called roll-to-roll method. In this case, the extensiondirection of the fragile processed portion may be parallel to thewinding direction. However, if the fragile processed portion is formedso as to be oblique to the winding direction, it is possible toappropriately prevent the occurrence of irregularities in the roll onwhich the laminated film is wound because the fragile processed portionis not present continuously in the winding direction. As a result, it ispossible to perform storage, transport, and the like appropriately.

The shape of the fragile processed portion can be changed in variousways other than the above. For example, the fragile processed portionmay be formed without removing the outer layer by performing so-calledhalf-cut processing using cutter processing, such as a rotary diecutter. In addition, the shape is not limited to the line shapeextending in one direction, and the fragile processed portion may have abent or curved portion, or may be formed in a linear shape obtained byconnecting a plurality of line segments to each other.

What is claimed is:
 1. A laminated film comprising: an inner layerformed of a linear low density polyethylene resin and is heat-sealable;an outer layer laminated on the inner layer; and an intermediate layerprovided between the inner layer and the outer layer, wherein the innerlayer and the outer layer form a fragile processed portion, from whichat least a part of the outer layer is removed and at least a part of theinner layer is present under the removed part of the outer layer, thefragile processed portion having a depth reaching at least an inside ofthe outer layer and not penetrating the inner layer, the intermediatelayer is an ink layer and is formed in a region excluding the fragileprocessed portion and excluding a periphery of the fragile processedportion in planar view, the intermediate layer being, in planar view,separated from the fragile processed portion, and a first laminationstrength between the outer layer and the inner layer in a region atwhich the ink layer is formed is less than a second lamination strengthbetween the outer layer and the inner layer in a region at which the inklayer is not formed.
 2. The laminated film according to claim 1, whereinan impact fracture mass of the inner layer is in a range of 100 g to 800g.
 3. A packaging container, comprising: the laminated film according toclaim 2, wherein the fragile processed portion is configured such that aplurality of small holes are configured to be formed therein duringheating by a microwave.
 4. A packaging container, comprising: thelaminated film according to claim 1, wherein the fragile processedportion is configured such that a plurality of small holes areconfigured to be formed therein during heating by a microwave.
 5. Alaminated film comprising: an inner layer formed of a linear low densitypolyethylene resin and is heat-sealable; an outer layer laminated on theinner layer; and an intermediate layer provided between the inner layerand the outer layer, wherein the inner layer and the outer layer form afragile processed portion, from which at least a part of the outer layeris removed and at least a part of the inner layer is present under theremoved part of the outer layer, the fragile processed portion having adepth reaching at least an inside of the outer layer and not penetratingthe inner layer, the intermediate layer is an ink layer and is formed ina region excluding the fragile processed portion and excluding aperiphery of the fragile processed portion in planar view, theintermediate layer being, in planar view, separated from the fragileprocessed portion, the ink layer is formed on one surface of the outerlayer, in a region at which the ink layer is formed, the ink layer andthe inner layer are bonded to each other with an adhesive, and in aregion at which the ink layer is not formed, the outer layer and theinner layer are bonded to each other with an adhesive.
 6. The laminatedfilm according to claim 5, wherein an impact fracture mass of the innerlayer is in a range of 100 g to 800 g.
 7. A packaging container,comprising: the laminated film according to claim 6, wherein the fragileprocessed portion is configured such that a plurality of small holes areconfigured to be formed therein during heating by a microwave.
 8. Apackaging container, comprising: the laminated film according to claim5, wherein the fragile processed portion is configured such that aplurality of small holes are configured to be formed therein duringheating by a microwave.